<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin:0;
            padding:0;
        }
        .wrap{
            display:flex;
            width:600px;
            height:600px;
            background-color: green;
            margin:100 auto;
            align-items:center;
            justify-items: center;
            perspective: 1000px;
        }
        .planet{
            width:200px;
            height:200px;
            border:2px solid #fff;
            /* margin:0 auto; */
            transform-style:preserve-3d;
            position: absolute; 
            border-radius: 50%;
            animation:planet-rotate 20s linear infinite;
            /* transform:scaleY(0.5) rotateZ(45deg); */
            /* 找到离她最近的position属性不为static元素的定位 */

        }
        @keyframes planet-rotate{
            0%{
                transform: rotate(45deg) scaleY(0.5) rotate(0);
            }
            100%{
                transform:rotate(45deg) scaleZ(0.5) rotate(360deg);
            }
        }
        .ball{
            width:50px;
            height:50px;
            position: absolute;
            border-radius: 50%;
            top:-25px;
            /* ball 穿过轨道 */
            /* 中心点重合 */
            left:calc(50%-25px);
            background-color:greenyellow;
            /* transform:scaleY(0.5) rotateZ(-45deg); */
            animation: self-rotate 20s linear infinite;
        }
        @keyframes self-rotate{
            0%{
                transform:rotate(0) scaleY(2) rotate(-45deg);
            }
            100%{
                transform:rotate(-360deg) scaleZ(2) rotate(-45deg);
            }
        }
    </style>
</head>
<body>
    <div class="wrap">
        <div class="planet">
            <div class="ball"></div>
        </div>
    </div>
</body>
</html>